How do I know how much lift my bladder needs?

[datamunk]

Okay guys so, I have confused myself on this matter...

I used to dive a diverite rec wing, worked fine with my steel 100 and weight i wore on my belt and bc.

However, am going to the venture wing now. My question is this.. Venture wing has 45lb of lift...

Now my question is this... With aluminum 80 i dive around 25 pounds (or used to) and with steel i dove around 12 pounds or so I believe (been a while).

The standard luxfer alum80 says this:
24.5lb water wegiht
-3.66 full and 4.0 empty in lbs both

Diverite expresses steel 100 is it is 33lb empty, bouyancy is -10.0full and -2.5 empty

So, my question is, will a venture wing with 45lb of lift be sufficient?

 

[Colliam7]

My question is this.. Venture wing has 45lb of lift... Diverite expresses steel 100 is it is 33lb empty, bouyancy is -10.0full and -2.5 empty So, my question is, will a venture wing with 45lb of lift be sufficient?

The answer is 'Yes'. In fact it may be more than enough, but there are other factors (diving environment, exposure suit, other gear, etc) that you will want to consider in asking and answering the question. But, there are LOTS of SB resources available on this one. The easy approach - go to the BC subforum (this is the 'General' equipment subforum, and check out the 'Wing lift calculator' at the beginning of the thread list. Do a search for Cool_hardware52 (Tobin, from Deep Sea Supply) and find some of his many posts that go through lift calculations, or PM him.

 

[crpntr133]

Should me well more than enough. I dive with about the same weight and use a 35# wing. #45 wing when I dive doubles.

 

[datamunk]

oh awesome, thanks guys.. yea i figured it would be, because, the weights make me just neutral etc etc, so, i dunno. blonde moment?

 

[docmartin]

Okay guys so, I have confused myself on this matter...

I used to dive a diverite rec wing, worked fine with my steel 100 and weight i wore on my belt and bc.

However, am going to the venture wing now. My question is this.. Venture wing has 45lb of lift...

Now my question is this... With aluminum 80 i dive around 25 pounds (or used to) and with steel i dove around 12 pounds or so I believe (been a while).

The standard luxfer alum80 says this:
24.5lb water wegiht
-3.66 full and 4.0 empty in lbs both

Diverite expresses steel 100 is it is 33lb empty, bouyancy is -10.0full and -2.5 empty

So, my question is, will a venture wing with 45lb of lift be sufficient?

45 is more than plenty (many would argue that it's too much). on a different note, diving with 25lbs on al80 and 12lbs on steel 100 obviously does not make sense so you must remember incorrectly. the steel will save you the difference between -2.5 and 4lbs and that's 6.5lbs and not 13lbs.

 

[Dive-aholic]

I'm one of those that will argue it's too much. You need enough lift to float your gear at the surface in fresh water. A 10lb negative tank plus 12lbs additional weight means you need 22lbs lift to make you neutral. Add a few lbs to make you positive - 30 lbs would be plenty. 45lb is going to create more drag in the water and cause your RMV to increase due to the additional workload of swimming it through the water.

 

[DA Aquamaster]

I'll argue the other poition and say more is nice to have. If you end up diving cold fresh water (very common) then you'll end up with up to perhaps 20-22 lbs of weight to sink a 7mm farmer john and the extra lift would be needed to float the unit at the surface if you take it off and are using integrated weights.

Also swells in fresh water are rare (great lakes aside) but short choppy waves are not uncommon and can be very uncomfortable if only your head is above water on the surface, the extra lift will get get you a few inches higher out of the water and can make being on the surface much more pleasant.

In my opinion, 45 lbs is about right for cold water diving.